Migrating an existing S7-200 application to an S7-200 SMART requires more than copying instructions. Many basic instructions remain similar, but hardware interfaces, communications setup, integrated libraries, high-speed counters, motion control, and programming software requirements differ.
Define the Migration Scope
Siemens discontinued the S7-200 beginning in October 2017 according to the available migration information, making S7-200 SMART the identified replacement family. Start by inventorying the original program's basic logic, PID functions, motion control, high-speed counters, communications, and library dependencies. Do not assume that similar instructions guarantee identical behavior in the specialized functions.
Compare Hardware Before Converting Logic
| Area | S7-200 | S7-200 SMART | Migration decision |
|---|---|---|---|
| Communications ports | One more COM port than SMART | One integrated COM port | Identify every device using the original serial ports and determine whether the available COM port, Ethernet, or a signal board can support the required connections. |
| Ethernet | Programming requires a dedicated cable in the described configuration | Integrated Ethernet supports programming through a standard network cable | Rebuild the programming and network communication configuration instead of copying the old connection settings. |
| Integrated I/O | CPU226 provides 40 points | SR60 provides 60 points | Map every physical point to the selected SMART CPU; do not infer address compatibility from point count alone. |
| Memory card | Siemens-specific card with limited capacity | Uses a commonly available card for program transfer, factory reset, and firmware updates | Include the card-based maintenance functions in the replacement and recovery plan. |
| Libraries | Users may need to create library files | Some libraries are integrated into the software | Check whether each original library function already exists before recreating it. |
Migrate the Program by Functional Area
- Basic instructions: Transfer and review bit logic, timers, and the other instructions shared by both families. Confirm operands and physical I/O mappings against the selected SMART hardware.
- PID functions: Isolate each PID dependency and migrate it separately from basic sequence logic. Retain the original control intent, then verify the converted implementation before commissioning.
- Motion control: Rework the motion portion as a dedicated migration task because its application differs between the two PLC families.
- High-speed counters: Review each counter configuration and associated input because high-speed counter usage differs from the S7-200 implementation.
- Communications: Reconfigure the network and serial connections around SMART's Ethernet port, single integrated COM port, and any selected signal board.
Prepare and Verify the Engineering Environment
The migration material identifies STEP 7 MicroWIN SP9 as incompatible with Windows 10 and specifies Windows 7 64-bit Ultimate for the S7-200 engineering environment. Preserve access to that environment when the original project must be opened or reviewed. The available evidence does not establish a direct, lossless project-conversion path, so verify the migrated application function by function.
Before replacing the controller, confirm the I/O map, basic sequence logic, PID behavior, motion functions, high-speed counter operation, and every communication link. Record unresolved library or hardware dependencies and complete controlled testing before returning the machine to service.
FAQ
Can an S7-200 program run directly on an S7-200 SMART PLC?
Many basic instructions, including bit logic and timers, are similar, but the evidence does not establish direct compatibility. Review PID, motion control, high-speed counters, communications, libraries, and I/O mappings separately.
How many integrated I/O points do the CPU226 and SR60 provide?
The S7-200 CPU226 provides 40 integrated I/O points, while the S7-200 SMART SR60 provides 60. Point count alone does not confirm that the original field wiring or addresses can be reused unchanged.
Can STEP 7 MicroWIN SP9 be used on Windows 10?
The migration information states that STEP 7 MicroWIN SP9 is incompatible with Windows 10 and specifies Windows 7 64-bit Ultimate for the engineering computer used in the migration workflow.